1. Field of Invention
The embodiment of the present invention relates generally to a control system and more particularly to a motor control system and a fan applied thereto.
2. Description of Related Art
When 5V and 12V motors are used in low rotational speed, the DCR cannot be increased by coil winding to lower the rotational speed for conforming to the demand standards due to the coil winding space being limited, wherein it is more difficult in 12V motor owing to it being easy to break the wire during manufacturing process in the condition of the wire being extremely thin. As such, the way to lower the rotational speed presently is to connect a resistor with the Vcc terminal of the motor control system in series so that the voltage provided to the IC can be lower to satisfy the demand of the client; however, there is a risk that the motor may be not activated.
In addition, if there is a demand for two kinds of rotational speeds, the prior art has to create two different current paths with switches to produce two different supply voltages for generating two rotational speeds; however, there will be additional power consumption produced from the resistor in the current path results in it being difficult to activate the motor. As such, the motor has to be drove in a high rotational speed when the motor is activated, and the motor is switched to a low rotational speed after the motor is activated. There will be a large noise during the activation of the motor.
In view of the above, the existing apparatus still has obvious inconvenience and defects and needs further improvement. In order to solve the above problems, those skilled in the art are trying hard to find a solution, but no applicable method is put forward. Therefore, it is one of important subjects and also a purpose in need of improvement that how to improve the power consumption due to cascade resistor, and the reduction of voltage provided to IC because of resistors connected in series so as to fail in conforming to the standards of the IC. Furthermore, it is important that how to improve insufficient energy outputted from the IC owing to the drop of the voltage so as to fail in activating the motor, and the large noise when activating the motor.